The present invention is generally related to beverage containers and is particularly directed to electronic drinking mugs for heating liquids to selected temperatures as well as to monitor the temperature of the liquid.
Individuals frequently drink soda, tea, water or coffee when traveling in automobiles. In order to facilitate this activity, automobile manufacturers have designed a wide variety of cup holders for securing beverage containers adjacent vehicle occupants. Some of these beverage containers are insulated for maintaining the temperature of a beverage. Unfortunately, insulated beverage containers cannot maintain the temperature of a beverage over a long period of time. This is particularly true of hot beverages, such as coffee and tea. As a result, a wide variety of heated cups and cup warmers have been developed. These heated devices typically have an electrical plug that is inserted into a cigarette lighter for providing power to the device.
U.S. Pat. No. 5,508,494 to Sarris et al. discloses a portable beverage cup made of thermally and electrically insulated material, such as injection molded plastic having a low-melting point. The beverage cup includes a heating element that warms the beverage and a retractable power cord that passes through an aperture in the container shell and is wound around the outer surface of the container in a helical manner.
U.S. Pat. No. 5,283,420 to Montal to discloses an electrically heated beverage container and holding stand for maintaining a heated beverage at a suitable drinking temperature. The beverage container includes a thin metallic cup-shaped insert having a positive temperature coefficient (PCT) ceramic heater affixed to a bottom wall thereof. An electrically non-conductive plastic sleeve encapsulates the insert and ceramic heater. The plastic sleeve has a film-like inner shell that promotes rapid heat transfer from the metal insert to the beverage in the container. A pair of electrical contact pins extend into a linear groove on the bottom of the container for mating with spring contacts located between a pair of linear guides at the top of the holding stand. When the container is mounted on the stand, an upstanding tab on the stand engages a recess in the container to positively restrain the container.
U.S. Pat. No. 5,243,684 to Edwards discloses a portable electrically heated container for liquids having a heating element secured to the bottom of the container by a support bar having its ends frictionally inserted into support slots. The bottom of the container is enclosed by a base cap separable from the container for providing access to the heating element. The heated container includes a power connection within the separable base cap and an indicating light to show a power-on condition.
U.S. Pat. No. 5,903,133 to Amero, Jr. et al. discloses a beverage holder and charger for use in a vehicle. The charger has a base that fits within an automobile beverage holder, an element for securing the base of the beverage holder, a first electrical contact on the base to supply power to the charger, a second electrical contact on the base to supply power to the item to be charged, and a receptacle on the base for holding the item to be charged.
U.S. Pat. No. 6,140,614 to Padamsee discloses an electric drinking cup for use while driving a vehicle. The electric drinking cup includes a plastic inner liner, a metal outer shell, and an insulation-filled space therebetween. A heating element is associated with the bottom portion of the inner liner, and is electrically connected to a vehicle's electrical system. The plastic inner liner curves around the upper edge of the outer metal shell providing a cup lip that does not get too hot when the cup contains a liquid. The combination of the plastic inner shell and the heating element provides a diffuse heat that heats liquid, such as coffee or hot chocolate, slowly to the desired temperature so that the liquid does not burn and become distasteful.
Despite these and other improvements in the art, still further improvements are needed in the field of heatable drinking mugs.